Study on op*cal levita*on of a mg-scale mirror ( 光輻射圧による鏡の光学浮上技術の開発 ) UTokyo, KAGRA Observatory, ICRR Koji Nagano ( 長野 晃士 ) (With a lot of support from Shotaro Wada, Takuya Kawasaki, Yuta Michimura, Takafumi Ushiba, Nobuyuki Matsumoto, and Masaki Ando) ICRR GW group seminar (Nov. 9th, 2017) 1
Self introduc*on • NAGANO Koji (D1) • Mainly in Hongo campus (table top). • Study topics – Gravita*onal wave detector • Input-output op*cs (IOO) • Main interferometer (MIF) – Opto-mechnical system – Macroscopic quantum mechanics ICRR GW group seminar (Nov. 9th, 2017) 2
Abstract • We are studying quantum noise in the gravita*onal wave detector and macroscopic quantum mechanics. • For these studies, interferometer which is dominated by quantum effect should be prepared although it can be hidden easily by environmental (classical) disturbance. • To avoid environmental disturbance induced by ordinary mechanical suspension system, we proposed new technique, op*cal levita*on of the mirror. • In this talk, op*cal levita*on will be Schema*c of op*cal levita*on. introduced and current experimental status will be reported. ICRR GW group seminar (Nov. 9th, 2017) 3
Outline 1. Introduc*on 2. Op*cal Levita*on 3. Current status 4. Summary ICRR GW group seminar (Nov. 9th, 2017) 4
Outline 1. Introduc*on 2. Op*cal Levita*on 3. Current status 4. Summary ICRR GW group seminar (Nov. 9th, 2017) 5
Introduc*on • Laser interferometer is a very precise posi*on measurement device and used to detect gravita*onal waves. • One of the major noise sources of the interferometers is Michelson interferometer. quantum fluctua*on of light. (Made by S. Kawamura) • Thus, we need to know the Strain [/rtHz] features of the quantum Quantum noise mechanics (QM) deeply to reduce the quantum noise (QN) and improve the sensi*vity of interferometers. Frequency [Hz] KAGRA latest es*mated sensi*vity. ICRR GW group seminar (Nov. 9th, 2017) 6
Introduc*on • In addi*on, this QN study leads to answer to one the most fundamental ques*on of physics: “ In the macroscopic world, does quantum mechanics hold?” • Surprisingly, we cannot answer this ques*on although QM is successful in the microscopic world, such as electrons, atoms, and so on. ??????? screen double slit electrons apples e - (micro) (macro) ICRR GW group seminar (Nov. 9th, 2017) 7
Introduc*on • In the macroscopic world, we have not seen quantum effect, such as super posi*on. • Is this because, ??????? – Just classical noise (CN) is large? – We need macroscopic quantum Deeply mechanics ? related!! • To confirm the situa*on, we should make various mass-scale systems which is dominated by quantum effect. • This is also necessary for the development of the reduc4on technique of QN of GW detectors. ICRR GW group seminar (Nov. 9th, 2017) 8
Introduc*on • Prior works Planck mass (~ 22 ug) membrane, suspended mirror, suspended 48 pg, Teufel+ 5 mg, Matsumoto+ mirror, (2011) (2014) 23--40 kg, GW detector (aLIGO, AdV, KAGRA) nanomechanical membrane, oscillator, 311 fg, suspended mirror, 7 ng, Peterson+ Chan+ (2011) 1 g, Neben+ (2012) (2016) mass fg pg ng g kg ug mg ICRR GW group seminar (Nov. 9th, 2017) 9
Introduc*on • Prior works Planck mass Almost QN dominant CN dominant (~ 22 ug) QN dominant membrane, suspended mirror, suspended QN dominant 48 pg, Teufel+ 5 mg, Matsumoto+ mirror, (2011) (2014) QN dominant CN dominant 23--40 kg, GW detector (aLIGO, AdV, KAGRA) nanomechanical membrane, oscillator, 311 fg, suspended mirror, 7 ng, Peterson+ Chan+ (2011) 1 g, Neben+ (2012) (2016) mass fg pg ng g kg ug mg ICRR GW group seminar (Nov. 9th, 2017) 10
Introduc*on • Prior works Planck mass Almost QN dominant CN dominant (~ 22 ug) QN dominant membrane, suspended mirror, suspended QN dominant 48 pg, Teufel+ 5 mg, Matsumoto+ mirror, (2011) (2014) QN dominant CN dominant 23--40 kg, GW detector (aLIGO, AdV, KAGRA) nanomechanical membrane, oscillator, 311 fg, suspended mirror, 7 ng, Peterson+ Chan+ (2011) 1 g, Neben+ (2012) (2016) mass fg pg ng g kg ug mg ICRR GW group seminar (Nov. 9th, 2017) 11
Outline 1. Introduc*on 2. Op*cal Levita*on 3. Current status 4. Summary ICRR GW group seminar (Nov. 9th, 2017) 12
Op*cal levita*on • Suspension system (for seismic isola*on) may introduce addi*onal classical thermal disturbance and can hide quantum effect. • To avoid the thermal effect, new technique to support mirror using only op*cal radia*on which is called as op*cal levita*on was proposed. radia*on pressure fluctua*on tension gravity gravity ICRR GW group seminar (Nov. 9th, 2017) 13
Op*cal levita*on Levitate the mirror only by op4cal radia4on pressure Isolate the system from the environment and make the system dominated by quantum effect Study quantum noise in interferometers Improve sensi*vity of Test of macroscopic gravita*onal wave detectors quantum mechanics ICRR GW group seminar (Nov. 9th, 2017) 14
Op*cal levita*on Study quantum noise in interferometers Improve sensi*vity of Test of macroscopic gravita*onal wave detectors quantum mechanics • See QN, in especially • Realize entanglement radia*on pressure noise in between the macroscopic advance of large scale mirror which can be seen!! detector. • Test of quantum gravity • Develop the reduc*on theory or objec*ve collapse technique of quantum in theory. table top experiment. • Ul*mately, lead to jointed • Leads to increasing of GW theory of QM and GR. event ra*o. ICRR GW group seminar (Nov. 9th, 2017) 15
Op*cal levita*on Study quantum noise in interferometers Improve sensi*vity of Test of macroscopic gravita*onal wave detectors quantum mechanics • See QN, in especially • Realize entanglement radia*on pressure noise in between the macroscopic advance of large scale mirror which can be seen!! detector. • Test of quantum gravity • Develop the reduc*on theory or objec*ve collapse technique of quantum in theory. table top experiment. • Ul*mately, lead to jointed • Leads to increasing of GW theory of QM and GR. event ra*o. ICRR GW group seminar (Nov. 9th, 2017) 16
Laser interferometer • Michelson interferometer (MI) is a device which convert phase change to power change as a signal. = Phase fluctua*on generates signal (or noise). Mirror mo*on Suspended mirrors (or Phase fluctua*on) Laser MI output Photo detector (PD) ICRR GW group seminar (Nov. 9th, 2017) 17
Quantum noise of GW detector • Quantum noise of laser interferometer = = QN is caused by vacuum fluctua*on induced • from signal port (= dark port). GW Bright Laser port Dark port Ponderomor*vely GW Vacuum (= through mirror signal fluctua*on mo*on) squeezed vacuum fluctua*on PD ICRR GW group seminar (Nov. 9th, 2017) 18
Quantum noise of GW detector • QN of ordinary (“classical”) interferometers Good ← Sensi*vity→ Bad Radia*on pressure noise ∝ Displacement sensi*vity [m/rtHz] Corresponding to mirror mo*on P ↑ Shot noise ∝ P ↑ ICRR GW group seminar (Nov. 9th, 2017) 19
Quantum noise of GW detector • QN of ordinary (“classical”) interferometers with homodyne detec*on = quantum measurement technique Good ← Sensi*vity→ Bad Displacement sensi*vity [m/rtHz] SQL can be beaten!! Improve sensi*vity! ICRR GW group seminar (Nov. 9th, 2017) 20
Op*cal levita*on Study quantum noise in interferometers Improve sensi*vity of Test of macroscopic gravita*onal wave detectors quantum mechanics • See QN, in especially • Realize entanglement radia*on pressure noise in between the macroscopic advance of large scale mirror which can be seen!! detector. • Test of quantum gravity • Develop the reduc*on theory or objec*ve collapse technique of quantum in theory. table top experiment. • Ul*mately, lead to jointed • Leads to increasing of GW theory of QM and GR. event ra*o. ICRR GW group seminar (Nov. 9th, 2017) 21
→ 単一光子で励起 修士論文審査会 単一光子源 の重ねあわせ状態を観測 の重ねあわせ状態を観測 基底状態の振動子 への到達が必要条件 それに相当する実験をし，重ね合わせが生じるかどうか検証する。 巨視的な物体では，直接二重スリット実験をする代わりに 到達が必要 提案されている検証方法 振動子の Macroscopic quantum mechanics • If we can prepare two mirrors whose mo*on was dominated by quantum effect, the mirrors are entangled. • Then, we can start to test of macroscopic quantum mechanics. These mirrors are entangled!! SQL に到達した振動子 ⟩ ⟩ diff. mode com. mode ⟩ ⟩ com. mode Sing PRM FI sour BS LASER ⟩ ⟩ ⟩ diff. mode bright port dark port Com. and Diff. mode 同相モードと差動モード PD PD is in super posi*on. com. mode diff. mode 2016/01/27 ICRR GW group seminar (Nov. 9th, 2017) 22
Op*cal levita*on • So far, two types (or more?) of OLs for mg- scale mirrors have been proposed. Y. Kuwahara, Master thesis, University of Tokyo (2016) sandwich type tripod type Y. Michimura+, Opt. G. Guccione+, PRL Express (2017) (2013) ICRR GW group seminar (Nov. 9th, 2017) 23
Op*cal levita*on • So far, two types (or more?) of OLs for mg- scale mirrors have been proposed. Y. Kuwahara, Master thesis, University of Tokyo (2016) sandwich type tripod type Y. Michimura+, Opt. G. Guccione+, PRL Express (2017) (2013) ICRR GW group seminar (Nov. 9th, 2017) 24
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